Milk product method of manufacture



Patented'July 8, 1952 UNITED MILK PRoDUo'r METHOD OF MANUFACTUREfleginald E. Meade, Appleton, Wis; assignor to Western CondensingCompany, San Francisco, Calif., a corporation of California.

Palestine 19, eiaiseri l No. 105,519

Q ""f4Claims;

This invention relatesgenerally to dry powdered milk products orconcentratessuch as are suitable for use'in bread making, and toprocesses for'manufactureof the'same,

.jIt hasbecome common practice inthe baking industryt'o use skirn milk'as aningredient in the preparation of .breaddough Generally the milk isadded in dry powdered form, together with wheat flour and other'jdough'ingredients, and sufiicient water is added to produce a dough of p p r fic 1 1' i i f vflltiriousproperties of skim milk powder affect itssuitabilitylfor'use in the bread'doughi Aside fronrsuch properties asaffect the bread with re spect'to itspalatability, flavor, crust (colorand tenderness) ,jtexture, loaf volume andkeeping qualities, it simportant that the added solids be capable of'jabso'rbing a substantialandpredeten mined am'ountof water informing a dough mix preesireeconsistency; A good quality of skim milk powderjsujch 'as has beenavailable on the market, and produced by processes involving heattreatment, vacuum evaporation and spray drying, 'afiords a waterabsorption of substantially 100%, In other. words, in preparing standarddoughmixes used in bread making, when such skim milk powder isadded tothe mix an additional amount of water can be added to an extent equal byweight'to the Weight'of the skim milk solids, without detrimentallyaffecting the plasticity of the dough. Because of the importance ofwater absorption efforts havebeen'made in thepast to increase theability of such material to absorb water, but without success. 1' 'It isa general object of the present invention to providejaipowderedmilkproduct having relatively good water absorption; and which isparticularly welladapted for use i'nbread making. ,Another object of theinvention is to provide a novel process for the'manufacture of my special powdered .milk product, whereby milk proteins, including.particularly" lactalbumin; are treated in a particular way to providehigh water absorption, and whereby 'the, amount of lactalbumi'n presentin the final product, in proportion to the other, milk solids, issubstantially increased I Additional objects of the invention willappear from the following description in which the preferred embodimenthas been set forth in detailin conjunction with the accompanyingdrawing. n

fReferring' to the drawing- Figure 1 is a simple flow sheet illustratingone embodiment of the invention.

(ems-556) 2 Figure 2 is another flow sheet illustrating anotherembodiment of the invention in which both skim milk and whey are used asraw materials The raw material used in carrying out the present processis a liquid lacteal material containing substantial amounts of milkproteins, ineluding lactalbumin. Both commercial skim milk and whey(including whey f obtained from the manufacture of. casein and wheyobtained as a by-product in the manufacture ot cheese) containsubstantial amounts of :lactalbumin, and can be used aswillbe'presently' explained. A sub:

stantial content of lactalbumin is essential be: cause I have discoveredthat in its absence, water absorption is relatively poor and thematerial is not suitable for bread making. V f V The present processinvolves the special conditioning of milk proteins while the lactealmaterial is 'in liquid form, and prior to conversion of the material toa dry powder, including par; ticularly the conditioning of all or asubstantial part of the lactalbumin present. In addition a part of thenon-coagulable and dissolved solids of the initial lacteal material'isremoved to provide a final product having a relatively high percentageof coagulable protein. The special conditioning includes coagulation ofproteins (including lactalbumin) by chemical action and heat treatment.t

The flow sheet of Figure 1 illustrates my proc-' ess as applied to wheyas a raw material. Whey is shown being supplied to the heating andacidulating operation I, which serves the purpose of coagulating andprecipitating proteins, including the lactalbumin present. Any suitabletype of heating equipment can be used for this purpose, such as willrapidly raise the temperature without-localized heating, and in practicegood results are secured by heating to a temperature of the order of 185to 280 F. The material is held at this elevated temperature forajprolonged period of time ranging inversely with increase intemperature, such as from 30 to 2.5 minutes. For example at temperaturesof the orderof 185 to 200 F., the time period can be of the order of 30minutes, for 240 F., 4 minutes, and for 2802K, 2.5 minutes. Variousacids can be used tolower the hydrogen ion concentration to theisoelectric point of the protein, and good results have been secured byusing themore common inorganic acids, particularly sulphuric acid, whichmay be supplied in diluted form. v Acidulation may be prior to, duringor immediately following the heating operation, without materialdifference in results.

When the higher temperaprecipitation of whey proteins, the materialissubjected to settlement at H for permitting the flo-cculent coagulatedproteins to settle to the bottom of the retention vessel. A substantialpart of the supernatant liquid is then removed; by decantation. Theamount of .liquid withe; drawn at this time is dependent upon the typeof product which is desired. Thus of the total liquid content of theoriginal whey it is desirable to remove at least about 33% of thesame'by decantation. The part thus removedis. discarded and contains aconsiderable. portion-of the dissolved solids of the milk,includinglactc'se.

Following. settlement. and decantation the 'material is. shown beingconcentrated by evaporation at. This can conveniently be carriedout byvthe use ofa conventionalvacuum evaporator.

After concentration the material is shown being treated with a-ne'utralizing agent at I3 for adjustment of' the hydrogen. ionconcentration, to thereby promote. redispersion of theboagulatedproteins. Suitable. reagents such as'sodium hydroxide, lime,.soda ash orsodium sesqui carbonate can be used for this purpose. Assuming that limeis being used, it may be. introduced in the form of a milk of lime (i.e. calcium hydroxide dispersed in water) in sufficient amount toadjustthe hydrogen ion concentration to about pH 6.0-to 9.0, a preferredrange being from pH The material isthen subjected to the spray dryingoperation [4, which can be carried out by the use of conventional spraydrying equipment in which the concentrate is atomized in contact withadryinggas. Although spraydrying is preferable to develop higher waterabsorbing properties, roller drying can be used ifdesired. As isunderstood by persons familiar with spray drying, the precedingconcentration by evaporation can be omitted if desired. Also suchconcentration can be carried. out after instead of before operation [3.

The, product obtained fromthe process outlined-in Figure i hasproperties which render it particularly well suited for use in. breadmaking. Itposesses all of the good properties. of present day highquality skim-milk powder, but it. differs from. conventionalproducts inthat it has relatively high water absorptivity. Products made accordingto. the present process have shown water absorptivity of the order; offrom 60. to. 90% (average-about 75%) inv contrast with about.33% forwhey treated and dried byfconventional methods. In. conventional breadmaking. where the. amountv of powdered skim ,milk added to the dough mixamounts to 6% oi the. weight of. the flour in the mix, the. use. of. myproduct in. place of conventional powdered, products permits. use. ofadditional water in. the mix, while retaining the. desired optimumplasticity for. the dough.

Removal of supernatant liquid after coagulation and precipitation ofthe. proteins serves to decrease the percentage of certain component i vFollowing operation it] for the coagulation and siderably better thancan be obtained for lactal- .bumin'spray dried in the absenceof othermilk solids.

-Lactalbumin appears to play an important part in attaining highabsorptivity, although absorptivityiappears to be in part due to othermilk proteins present, including casein. Because of coagulation andprecipitation of the milk proteins followed by, dispersion by adjustmentof the hydrogen. ion'concentration, the proteins are in a denaturedform, and it appears that such denaturing orconditioning of the proteinscontributes to high absorptivity in the final product.

It is possible to alter the procedure of Figure .1 in various respects.Thus only part of the whey may. be. subjectedtosettlement anddecantation, and the. material remaining after 'decantation thenremixed" with the rest [o-fjthe .whey for fur:- ther treatment. Also itis, possible to produce various blended. products,[as'by blendingthemateriaLfrom. operation ll'..with a separately introduced skim "milkprblending the concentrate from i3,wi'th.skim milk concentrate.

' The flow sheet, oiFigurfZ illustrates aproccss in which both skim milkand whey are used as sources ofmaterial. Thus separate. amounts of skimmilk and whey arev subjected tothe heating and. retention operations 2[and 22,..which. can be. at. an,elevatedjtemperature of" the order 'offrom .185=to..200.. Fl,-fora period, of the brder. of 30Iminutes- Hereagain as in. Figure 1. higher treatment temperatures. can. be. used forshorter periodsmottimes The two heat treated materials are combinedat-lii. and themixture aci'dulated by. addition of a. suitableacid;,.such as dilute sulphuric acid, for coagulating. and precipitatingthe proteinspresent. Thematerial is then. subiectedgfto settlement. anddecantation at 24 where a substantial. part; of the supernatant liquid.is;.remo.v.ed. The remaining. materialis then. subjected. to,concentrationby evaporation at 25,..after, whicha suitablejneutralizingagent, such as milkoflime, is added. to the material. in operation. 26to adjust thehyd'rogen ion' con.- centratibmto. a. value of the order offrom. pH 6.0 to 9.0.. The. materialis then subjected to spray drying at2.1. to. produce a final powdered product.

. By following. theprocedure outlined in Figure 2ji-t. is possible toproduce adry powdered product suitable for bread making. and; whichwill. provide. amoisture absorptivity of the order. of from to 200. Theprocedureof Figure 2 isdesirable where. a. supplyotinexpensive whey isavailable, and. where, it necessary to provide a moisture absorptivitywhich. isgreater than can be obtained'. by the. use of liquid, whey byitself.

. It, is. possible to employ variations of the above describedprocedures to produce the desiredproductj Forexample I can employ theprocess of Figure I to produce a concentrate from whey, and then mix thesame with a treated skim milk. The treated skim milk can be prepared byaci'dulation, heat treatment and adjustment Of the hydrogen. ionconcentration in the same manner as the steps In and ['3 of Figure 1'. Ablend of the two materials, that is of the treated. skim milk (with orwithout concentration) and the treated concentrate from whey, can thenbe spray dried-to form a final powdered material. It'is also possibletos'eparately spray dry 'the con centrate obtained fromwhey according toFig-l ure 1, and a skim milk treatedas described above, thus'producingtwo' powdered products, which are thenintermixed together, to formtal/final blended-product i J Another possible variation-ofthe? processis to blend the material remaining after decantation ll. (Figure'l)witha quantity'o'f untreated skim milk, after which the blend is heattreated, acidified, concentrated by vacuum evaporation, neutralized, andspray dried,-all"as previous'lydescribed. f

In the foregoing embodiments of the invention the whey is-heat treatedin conjunction with aci'dulatiom'and its" hydrogen ion "concentration isadjustdby the use ofa"neutralizing agent, after settlement anddecantation. It has -been found possible to secure the desiredcoagulated efiect by employing acidulationiollowed by neutralizationwith lime, prior to the heattreatment: Thus diluted sulphuric acidcan'be introduced into the whey to provide'a' hydrogen'ion concentrationof the order of-pH 4.0 to' 5.6, after which milk of lime is introducedto"pro'vide'a hydrogen ion concentration of the order of from pH 6.0 to.9.0. Thus as atypical example good results canbe secured by acidulationto"pH 4 .5, followed by neutralization with lime to. pH 6.5; Thismaterial can then beheat treated in the manner :previously 1 described,whereby lactalbumin and other milkzprotein :p'resent is coagulated andprecipitated. 1 Following such heat treatment the material can besubjected-todecantation, and the material remaining rafter decantationspray dried, either with or without previous concentrationbyevaporation, p

centrat'ion to ::;pH 20.5; ii'con'centrated rloyr vacuuni evaporation'a'nd then'con-verted'to a dry powder bv spr'ay dryingr Y i- The productobtained by the foregoing example had a moisture absorption of about75%. When tio'nal dried'whey with a lesser mount or water.

I A a i Examplell: I l 'ZPIQ b -T of wi lk mmi k as' e to 2. .0 for aperiod of '30 minutes. 600 1b's. o f' weet Cheddar cheese whey wassimilarly heate dito a temperature of 200 F. for a period of minutes Thetwo quantities were combined while held at the temperature of 200 F.,and then'acidulated by addition of dilute.(20%) sulphuric acid, to ahydrogention, concentration of pH 4.65.:As .a

- "Inythe above embodiment oftheprocess itap pears thatthe presence of'calciumvsulphate; -formed by reaction between the sulphuric acid andthe: lime, during heat treatment, 'causes'an effect upon'the lactalbuminand other protein present similar to, the effect in the previouslydescribed embodiments; where the acidulated ma? terial is heat treated;before thelimeyorjother neutralizer israddedr Thus as a furthermodification of the process a mineral. saltsuch as cal? cium sulphate isadded to a neutral whey in an amount substantially; equivalent; to thesalt formed when the acid and neutralizerjare. added separately.Withapplication of the heat treatment the protein is coagulated ordenatured in substantially the same manner, although it appears thatthewater absorptivity of the resultn: powder i a o as i as; wh n th a dand neutralizer are added successively; gThe same treatment ;just decribed above can Zalso.;be applied to skim milk: beingprepared forblending Withithe -treated and: decanted whey, lifxamples of; actualpractice are as follows:

a Example I Fresh cheese Whey washeated' to'a temperature of 200 F. andheld at this temperature for-1a period of 30.minutes; Ardilut' (20%)'solution of sulphuric acid was added to adjust the-hydrogen ionconcentration to pH 4.65; The'coagulated protein precipitate thereby,"-formed waspermitted to settle and supernatant liquid 'was removed bydecantatio'n' to the extent ofjleaving of the original volume ofwheyL-a- The residual material. was then neutralized by the addir tionof milk of lime (10% calcium hydroxide dis:- persed in water) toadjustlthe hydrogen iOITCOn:

result, proteins including lactalbumin werewo-v agulated 'andprecipitated,v and "the precipitate permittedto settle. 600* lbs. ofsupernatant liquid was then decanted on and the remaining material wasconcentratedfl-by,vacuum evaporation jand -,spra'y dried. to rorma"final powdered product. The powder'analyzed-pas"follows: v

Erample III :1

quantityfof skim milk wasfheated 1313 20091. and held at this,temperature for "30 minutes.

Thisfmilk was thenconcentrated to 20 solids content by vacuumevaporation; A quantity of fresh Cheddar cheese whey'was heated to 200?13, ilu 3. 9I5l 1 hl Ii a d added 9 di silt s eeper wmfmtmfi ng o;PHAQ nd. the

'rqr iajperiodfot min-'- rotein 1 precipitate settled retention;Supernatant liquid was removed by decantation, and the residualprecipitate was twice washed with fresh EwaterTfollovved by settlementand "decantation. The washed concentrated "slurry was then neu tralizedbyiadditionll of dilute 10 sodi'u'rn" 'hydroxide solutiontito a hydrogenion-concentration of pr-r 65. Theh eat treatecl skim milk-con centratei: and the lactalbumin' concentrate" were their combined in twodifferent ratiosi to" provide two. different-products having 1 differentcontents of' lactalbumin' One product e? contained about one part oflactalbumin derived from the whey, to fiveipa'rts of solids'derived fromthe'skiin milk. The second product" contained one 'part of lactal buminobtained from' the'whey, and eleven parts of milk solids obtained -fromthe; Skim milk These productehad water absorption of 200% and 166%respectively, andwhen used inbread making gave good results wlthrespectto the characteristicsrof the loaf obtained.-

'5 E m IV r 600 "lbs. ofwhey was heated to 200 F.- fora period of'iiqj-minutes. 240 lbs, of. skim milk was likewise heatedto 200? Frforaperiodof=30 min-- utes: The eat tr a d y a d im milkportionsawere thenmixed and suflicient dilute sulphurie aeid.:;-added t adjust the, hydr ncpncentration to pH 4.65. The mixture was permittd;t;stand to settle theprecipitate, and then a -quantity of supernatant liquid decanted 1offuntilvthe;-remaining;-volume equaled the initial volume of the skimmilk. The material was then adjusted to a hydrogen ion concentration ofpI-I 7.0 by addition of a dilute solution of sodium hydroxide,concentrated by .vacuum evaporation, and spray dried.

Thematerial produced-as described above analy ze dl as follows: I v.Moisture per cent 1.!

Acid do 113 Lactose"- do 47.7 Protein do 37.1 Ashi do 10.3

' "Th in oduc'tpbt i d fro the o o g xamplehadfa water absorption of166.6% and was similarincharacteristics to the product obtained fromExample II.

Example V 125 lbs. of skim milk was heated to 200 F. for aQperiod ofminutes. 250 lbs. of whey was prepared by heating skim milk to 105 F.,and then adding sulphuric acid to adjust the hydrogen ion concentrationto pH 4.65 and thereby precipitate casein. The whey decanted from theprecipitated .material was added to the heat treated skim milk and themixture, while at a temperature of200-F., was acidified by addition ofdilute sulphuric acid toadjust the hydrogen goinjgj ekam'ple hadall ofthe desirable properties.

of the. product obtained according .toExampleII, and hadawaterabsorption of 166%. t

mm w

, --2500; lbs. of whey was' heated to;-l90 F and then mixed with 500lbSpOf skim milk, which had likewise been heated to 190F. The mixturewas held atthistemperature for a period of 30 minutes,-and ;the hydrogenion concentration ad"- justed to pH 4.8 by addition of dilutesulphuricacid.- The coagulated protein was allowed'to SBUJIE, and ,sufllcientjsupernatant liquid decanted ofito leaveja-volume-bf material equal tothe original volume of skim milk. The hydrogen ion concentration of thismaterial was adjusted to pH 6 28' by addition of sodium hydroxidesolution, afte Which "the material. was concentrated byvacuumevapqration and spray dried.

The product produced by the foregoing examplehad all of the desirableproperties of the product obtained from'Example II, and had a waterabsorptionwof 200%.

Although the preferred formof the product is azdry powder, it ispossible to use the, treated liquid in concentrated form (without spraydrying) for the preparation of dough mixes aspreviously described,provided the water content of the'mix. is adjustedaccordingly; It isdesirable however that such. concentrates ,have at. least 50% solids. IAs shown by the foregoing examples my product is a decided improvementover prior skim milk products, particularly with respect to its highwater absorptivity; My process is relatively simple to-apply,commercially for low costquantity productiontosupply the needs of thebaking industry v p 1., In a process for the manufacture of a drypowdered product having high Water absorptivity when used inbread dough,the steps of coagulating milk protein of a lacteal material containingthe proteins of whey, such coagulation being carried out'by increasingthe mineral content of the lactealmaterial and by heat treatment to atemperature of the order of from 185 to 280 subjecting the material tosettlement and decantation, removing a supernatant liquidrelatively'free of coagulated protein to-reduce' the original volume ofthe material by not more than about/50%, and then converting'theremaining material to .a dry powdered product. '2.In'a process forthe'manufacture of-a dry powdered product having high water absorptivity'when used in bread dough, the steps of treating liquid whey tocoagulate its lactalbumin, said treatment being carried out'byincreasing the helm of whey, the steps of coagulating'milk-pro tein's ofthe lacteal material by heating the material to a temperature of theorder of from 185 to 280 fora period of time from-"30 t0 2.5 minutes andalso by acidulating' the material to a hydrogen ion concentration ofthe'order of pH 4.0 to 5.6, and by neutralizing the acidity to provide a pHvalue of from 6.0 to 9.0-, subjecting-the 'material to settlement anddecantation to remove a supernatant liquid from the'r'emaining materialto reduce the original volume of the material by not more than about50%, the liquid being substantially free of coagulated protein, and thenconvertingathe remaining material to dry powdered form.: I

- =4; -In a1process for the manufacture of a dry product' having highwater absorptivity when usedin'bread dough,heating quantities of skimmilkand whey to a temperature of the order of irom 1 to 280: F.-for aperiod of time ranging inversely 'from 30 1302.5 minutes-and increasingthe miheral'content of the material to'denature protein, subjecting thematerial to settlement and decantationlto remove a supernatant liquid toreduce the original volume" of; the skim milk and whey, neutralizing theremaining material to a hydrogen ion concentration of the order of frompH 6.0 to 9.0. and then converting the material to dry powdered form.

REGINALD E. MEADE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 442,593 Rehnstrom Dec. 9. 1890482,897

Frederiksen Sept. 20, 1892 10 Number Name Date 664,318 Hall Dec. 18,1900 1,557,181 Messmer Oct. 13, 1925 1,870,270 Washburn Aug. 9, 19322,023,014 Flanigan et al. Dec. 3. 1935 2,181,146 Peebles et a1 Nov. 28,1939 OTHER REFERENCES Rogers, Associates of, "Fundamentals of Dairyscience," published 1928 by The Chemical Catalog Co. Inc., N. Y. city,pages 46, 53, 51.

Hunziker, O. F., Condensed Milk and Milk Powder, published 1946 by theauthor, La Grange, Illinois, 6th edition, pages 17, 19, 240.

1. IN A PROCESS FOR THE MANUFACTURE OF A DRY POWDERED PRODUCT HAVINGHIGH WATER ABSORPTIVITY WHEN USED IN BREAD DOUGH, THE STEPS OFCOAGULATING MILK PROTEIN OF A LACTEAL MATERIAL CONTAINING THE PROTEINSOF WHEY, SUCH COAGULATION BEING CARRIED OUT BY INCREASING THE MINERALCONTENT OF THE LACTEAL MATERIAL AND BY HEAT TREATMENT CONTENT OFTEMPERATURE OF THE ORDER OF FROM 185S TO 280* F., SUBJECTING THEMATERIAL TO SETTLEMENT AND DECANTATION, REMOVING A SUPERNATANT LIQUIDRELATIVELY FREE OF COAGULATED PROTEIN TO REDUCE THE ORIGINAL VOLUME OFTHE MATERIAL BY NOT MORE THAN ABOUT 50%, AND THEN CONVERTING THEREMAINING MATERIAL TO A DRY POWDERED PRODUCT.